Electrically actuated operationcontrolling device



Feb. 29, 1944. DEN BESTEN ET AL 2,342,925-

ELECTRICALLY ACTUATED OPEBATION-CONTROLLING'DEVICE 42 a 355 ,493 35 44 ENVaN'TOR-EL C/YbQr/ Den Bea/en C0/'/ Cf @z/ermuna 24 e 43 1 M WYAAM OQTTOQEYS Patented Feb. 29,

UNITED-STATES PATENT OFFICE ELECTRICALLY ACTUATED OPERATION- CONTROLLING DEVICE Gilbert Den Besten and Carl J. Klermund, Chicago, Ill.

Application August 4, 1940, Serial No. 351,290

4 Claims. (01. 236-75) This invention relates to improvements in electrically actuated operation-controlling devices and more particularly concerns an arrangement including as a motivating force an alternating current solenoid.

Alternating current solenoids have heretofore been impractical for many uses because of their noisiness due to hum and chatter in operation. Humming occurs when the armature fails to contact the cross head of the solenoid squarely in the center so that there is an improper clearance between the side of the armature and the wall defining the flux chamber. Chatter is the result of vibration of the armature caused by the flux impulses generated within the solenoid by the alternating current. Due to this noisy character of alternating current solenoids, use thereof for operations requiring anything more than momentary energization of the solenoid has been frequently out of. the question, although for many purposes this type of solenoid, without the deterrent factor referred to, would prove more economical, be more eflicient in operation andrequire less auxiliary equipment.

An object of the present invention is to provide an electrically actuated operation-controlling device including an alternating currentsolenoid automatically controlled to remain silent during energization of the device even for relatively prolonged periods of continuous action.

Another object of the invention is to provide a device of this character including means mechanically cooperative with the armature and the stator structure of the solenoid to locate and hold the armature in a hum-free and chatterfree position within the flux chamber of the stator while the solenoid is energized.

A further object of the invention is to provide a solenoid-actuated operation-controlling device including solenoid silencing means which serves also as means for connecting the armature of the solenoid to the apparatus controlled by the device.

Still another object of the invention is to provide an improved silent solenoid device for controlling the operation of a draft regulating damper.

An additional object of the invention is to provide an electrically actuated operation-controlling device of the foregoing general character "which is of relatively simple and inexpensive construction and can be supplied as a lightweight, compact unit. 5

.Other objects and advantages will become air-'- parent in the following description and from the accompanying drawing in which:

Figure 1 is'a front elevational view of an operation-controlling unit and associated mechanism embodying the invention with certain portions broken away and in section for clarity of disclosure, and with the parts in the relationship assumed when the solenoid is deenergized.

Fig. 2 is a vertical sectional elevational view taken substantially along line 2-2 of Fig. 1.

Fig. 3 is a partially sectional, fragmentary front elevational view of the lower portion of the control unit showing the position of-the parts during energization of the solenoid. I

Fig. 4 is a transverse horizontal detail sectional view taken substantially in the plane of line 4-4 of Fig. 1,'and showing the shading coil in the cross head of the solenoid.

While the invention is susceptible of various modifications and alternative constructions, we

have shown in the drawing and will herein describe in detail a preferred embodiment, but it is to be understood that.we do not thereby intend to limit the invention to the specific form disclosed but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims I By way of exemplification, the invention is shown in the drawing as embodied in a solenoid actuated unit Ill for controlling the operation or a flue draft regulating damper II. The damper is of the type known in the trade as a barometric damper and 'pperates on the principle of admitting measured quantities of atmospheric air through" an inlet into the associated flue passage proportionate to fluctuations in pressure differential between the outer atmosphere and the flue draft over a predetermined setting of the damper. That is, the'damper plate is swingably mounted in traversing relation within the air inlet so that during firing periods it will restrain inflow of air up to a certain pressure whereafter it responds to the pressure diiierential created by a draft-induced drop in the internal pressure to swing open for admitting atmospheric air into the flue passage. The damper plate automatically resumes its adjusted inletclosing position when the flue pressure resumes the predetermined value for which the dampe has been set. In the non-firing condition of the heating apparatus it is desirable to substantially check the draft and for this purpose the. damper is held open to admit free inflow of air through the inlet into the flue passage. During heat demand periods, however, a certain draft intensity or pressure is required for proper combustion, and at such times the damper plate must be released to its air-flow controlling position for free barometric operation. For this purpose the armature of the control device solenoid is connected with the damper plate to hold the latter open in check draft position during non-firing periods, and releases the damper plate for free barometric action during heat demand periods. Since the heat demand periods usually cover a substantial time interval, it will beapparent that the solenoid must operatesllently in order to be practical for this use.

Referring more particularly to the drawing, the damper II includes a tubular inlet I2 which may be in the form of a stub pipe attached upon a horizontal axis to a flue pipe I3 or other breaching forming a passage leading from the associated heating apparatus (not shown) to a chimney or directly to atmosphere. Mounted at the mouth of the inlet I2 is an embordering frame in the present instance comprising a ringshaped casting l4 which has a damper plate I5 pivotally mounted upon an eccentric axis therein by means of a horizontal shaft I! which extends in chordal relation across the inside face of the plate. The plate I5 is thus divided into upper and lower small and large segments, respectively, tending normally to overbalance the plate into traversing or air flow restraining relation to the inlet I2. Means for adjusting the responsiveness to air pressure of the damper plate I5 may consist of a counterweight I8 mounted upon a longitudinally shiftable arcuate carrier I9 slidably supported by passing through suitable vertically spaced bearing apertures in the plate and through a guiding and locking arm 20 which projects from the outer face of the plate. In the non-firing condition of the heating apparatus, the damper plate I5 is adapted to be held in fully open position against a limiting stop 2I projecting radially inwardly from the embordering frame I4 (full line position Fig. 1 and broken line position Fig. 2) so as to admit air freely through the inlet I2 into the flue passage to check the draft. During heat demand periods, the damper plate must be released for free swinging predetermined airflow restraining or barometric action in the inlet I2.

In the present instance the operation-controlling device It is constructed as a small, compact unit of such comparatively light weight that it can be conveniently secured to and supported directly by the draft regulator II at the mouth of the inlet I2. In this way an efficient short operating connection with the damper plate I5 can be provided. Accordingly, the unit includes a solenoid 23 mounted for protection and neatness of appearance within a housing 24. The stator of the solenoid comprises a coil 25 having therein longitudinal flux chamber 26 and retained between opposite end plates 21 which are axially apertured to form openings for the opposite ends of the flux chamber. The coil assembly is mounted longitudinally within a medially encircling, rectangularly shaped magnetizable bar metal frame 23 which fixedly engages the end plates 21. At one end the magnet frame 23 is open as indicated at 29 in registration with the mouth of the flux chamber 26 and at the opposite end the frame provides a cross head 30 across the associated end of the flux chamber. Through this arrangement an armature 3 I, herein preferably of rectangular cross section, can work reciprocably through the mouth of the flux chamber 26 to abut the cross head 30 when the solenoidis energized. The cross sectional dimension of the armature 3| is such relative to the flux chamber 26 as to afford ample clearance for longitudinal armature movement.

Herein the housing 24 includes an elongated body member 32, of generally U-shape longitudinally, and an elongated transversely U- shaped closure member or cover 33 cooperating therewith to form a substantially rectangularly dimensioned box-like enclosure for the solenoid 23. The body member 32 may conveniently be formed of suitable strap. iron while the cover may be fashioned from suitable gauge sheet metal to provide a relatively light weight, resilient shell. The side wings, and inturned narrow flanges 34 at theends of the cover 33, frictionally engage the end and side margins of the outer housing leg faces and hold the cover in place but enable it to be slipped on or oil as occasion demands.

The solenoid 23 is mounted longitudinally within the housing 24 and for this purpose may be equipped with means such as angular hangers or brackets 35 at the cross-head end thereof. These brackets 35 are secured to the inner face of one leg of the housing member 32 as by means of stove bolts 31 which, for the purpose of dampening possible vibration from the solenoid, are preferably resiliently seated as by means of rubber grommets 38. The clearance between the mouth end of the stator and the opposite leg of the housing member 32 is sufficient to enable the necessary range of longitudinal movement of the armature 3|. As a result of this arrangement, when the housing 24 is mounted in a vertical position with the cross-head end of the solenoid uppermost, the armature 3| may fall gravitationally partially out of the flux chamber 23 for a predetermined distance limited as by engagement of the lower end of the armature with the lower leg of the housing member 32.

In the illustrated environment, the solenoid housing 24 is secured vertically in generally depending relation to the lower edge of the embordering frame I4 at the mouth of the inlet I2. For this purpose, a laterally outwardly and downwardly projecting attachment flange or ear 39 (Fig. 2) may be cast integral with the lowest portion of the frame I4, and the housing body member 32 is secured to the outer face thereof as by means of screws 40. Vibration dampening means such as a rubber pad 4| may be interposed between the housing and the attachment flange 39. By preference the upper end of the housing member 32 and the dampening pad 4I extend slightly upwardly into the path of the damper plate I5 to serve as stop means engageable by the lower portion of the plate for limiting the outward swinging or closing movement thereof. By this arrangement, moreover, the

solenoid control unit III is located at the mouth of the inlet I2 in the path of the cooling flow of indrawn air.

Reciprocal activity of the armature 3| effects control over the damper plate I5 through the medium of a flexible connection in the present instance comprising an armature-engaging member 42 and a damper-plate attached member 43.

The armature engaging member 42 )s preferablybar 44 secured to the lower portion of the armature 3i, and substantially parallel side bars 45 extending upwardly from the ends of the base bar along the sides of the magnet frame 28 to project at all times through appropriately located apertures 46 in the upper leg of the housing member 32. The upper ends of the side bars 45 are connected together by a top bar 41. The entire connecting frame member 42 may be formed of one strip of noncorroding sheet metal such as phosphor-bronze.

The damper-plate attached member 43 may be fashioned from suitable non-magnetic wire substantially into the shape of a parallel-leg, U- shaped bail straddling the adjustment arm 20 and having the end portions of its legs extending loosely slidable through apertures 48 in the upper bar 41 and bent over at the extremities to provide retaining fingers 49. The upper or transverse portion of the bail member 43 may be formed with a central twisted eyelet 50 to receive the eye portion of a cotter member which is secured through an aperture 52 in the upper portion of the damper plate I5 above the adjustment arm 20.

Th connecting members 42 and 43 are so proportioned that when the armature 3| is in its lowest position the frame member 42 is drawn down therewith and through the interengagement effected by the fingers 48 also draws down the bail member 43 to pull the damper plate [5 to its open or check-draft position as shown in Fig. 1. During heat demand periods in the associated heating system. however, the energized solenoid 23 draws the armature 3| and the connecting frame 42 up, thereby releasing the damper plate for free barometric action. In the latter condition the damper plate is allowed to move freely by reason of the pivotal connection between the eyelet 50 and cotter member 5| and the free sliding movement permitted for the ends of the bail member 43 through the apertures -28. In fact, this relationship is such that the damper plate can without hindrance swing fully open as indicated in broken line in Fig. 2 under the influence of infiowing air. To avoid possible sticking or sluggishness in operation and to insure prompt opening of the damper for check draft purposes when the solenoid is deenergized, means may be provided for compelling prompt descent of the armature 3|, in the present instance comprising a weight 53 suitably secured to the lower end ofthe armature. In practice the solenoid 23 may be "connected as by leads 54 to the electrical damper or burner control circuit (not shown) of the associated heat producing apparatus.

An important feature of the invention resides in the means whereby the solenoid 23 is maintained silent during alternating current energization thereof even though it is kept in operation for substantial periods of time. In the present instance this silencing is effected by a mechanicalsilencer arrangement which operates automatically upon the armature 3| as an incldent to assumption of the energized condition of the device, whereby to assure freedom from hum or chatter. For convenience, the mechanical silencer may comprise the connecting frame base bar 44 and the adjacent lower portions of the side bars 45 which are formed as inwardly bent centering members or engagement pads 55 adapted to receive the lower 'end of the magnet frame 28 in snug slidable relation therebetween. Although the remaining portions of the side bars 45 are-spaced to remain clear of the magnet frame, the centering pads 55 are designed to engage gradually with the lower corners of the solenoid frame member 28 before the armature 3| strikes the cross head 30 and to be in full 5 engagement therewith at the end of the up stroke of the armature (Fig. 3), thereby assuring a substantially centered relationship of the armature within the flux chamber 25. Moreover, the base bar 44 may be so located or formed that it will strike thelower face of the magnet frame 28 slightly before the armature 3| engages the cross head 30 so that a slight flexing thereof will occur in th final inward movement of th solenoid, thus assuring tight armature-centering engagement between the silencer bar and the magnet frame. The comparatively yieldable nature of the material of the connecting frame 42 enables proper adjustment of the centering relationship as well as'the gripping tension of the centering pads 55. Asa result of the enforced armature centering and thus proper spacing between the armature 3| and the walls defining the flux chamber 26, hum is avoided, and by the holding of the armature against side play under ggthe influence of the flux impulses, chatter is avoided. 5

Additional means for assuring silent operation may comprise a shading ringer coil 56 (Fig. 4) preferably mounted flush centrally within the so armature-engaging face of the cross head to further assure centered, movement-free positioning of the inner end of the armature. This expedient is particularly valuable where improper tolerances-or sloppiness occurs accidentally or from wear in the mechanical silencingmeans which might allow the armature to tilt as it apporaches the cross head 30. The shading coil being preferably formed of copper or an alloy thereof, it serves also to form a permanent flux a gap between the cross head 30 and the armature II to assure instantaneous release of the armature upon deenergization of the solenoid even though a tendency toward permanent magnetization may develop in the cross head.

present invention provides an improved solehold-actuated operation controlling device which can not only be produced as a light-weight compact unit of relatively simple and inexpensive eration controlling solenoid structure including a casing, means forming a vibration dampening connection between said casing and said device, a stator having a vibration dampening connection within said casing, an armature reciprocable within said stator, means for maintaining said stator and armature substantially silent in operation, and means for operatively connecting said armature with a movable part of said device.

2. In combination in apparatus of the character described, a supporting structure, a member to be controlled mounted for swinging movement on said supporting structure and having a From the foregoing it will be apparent that the apparatus to be controlled. This arrangement weight distribution tending normally to position the member in a given relation to said supporting structure, a solenoid carried by said supporting structure below said member and including a stator and an armature vertically reciprocable from a gravitationally assumed position partially below the stator and an energized position well frame to be drawn down to its lower limits in the deenergized condition of the solenoid for drawing said member out of its normal position and being adapted to be drawn up by the armature in the energized condition of the solenoid to an elevated limit position wherein said member is released to reassume its normal position, the horizontal dimension of the frame being such throughout its vertical extent except adjacent to the lower end of the frame to beentirely clear of the stator for complete freedom of movement, and adjacent its lower end being of a reduced width to engage with the opposing side surfaces of the stator in the last part of the upward movement of the frame upon energization of the soleacid to hold the armature centered within the stator and prevent chatter or hum in the solenoid.

3. An operation-controlling device comprising, in combination. a solenoid including a stator having a longitudinal flux chamber, an armature longitudinally reciprocable within said flux chamber, said armature being movable to a substantial extent beyond one end of the stator in the stator but permitting complete freedom of movement of the armature and remaining out of contact with the stator throughout the majorextent of reciprocal movement of the armature. 4. An operation-controlling device as defined in claim 3 wherein the arms' are substantially longer than the stator and have means opposite their stator-engaging ends for connection with an instrumentality to be controlled by the movements of the armature.

GILBERT DEN BESTEN.

CARL J. KLERMUND. 

